BigRat,
Interesting observations. As far as you managing to counter the double immel - it appears even a vertical turn fight is still a turn fight and thus advantages the tighter turning Hog. I think I've observed this before, getting locked into a looping fight in something like a 190 vs Hurri. Even though I had a decided climb advantage, I still couldn't out turn him - he could always force a HO if he desired.
Regarding lazy vertical extension - I guess it's philosophically of matching one extreme with a different extreme. The 109 we've assumed has turned very aggressively for a gunshot, dumping E for angles. My initial reaction was to do the most opposite thing possible - extend and conserve E and let him drop off because he can't keep up.
Granted, a turn fight is just what a hog wants, even if it's vertical so maybe my initial reaction was from flying great climbers too long. So in this case (and this agrees with what you found), you have more room to be more aggressive as the Hog owing to your better turn.
Psychology - I'll keep that in mind in the future. I tend to fly pretty cold, so the amount people panic surprises me a lot.
I snuck up on a semi-afk Zero once (he was there, but had terrible SA, I climbed up behind him and he didn't react at all) and opened fire. I got some hits, but it didn't kill him, and he dove away. I'm in a K4 so I think to myself... oh boy... he's going to force a turn fight so I move to break away.
After I break off, I roll to put my canopy on him and see what he's doing. I see this guy about a mile beneath me turning wildly and spraying his guns into thin air. I must have made him piss his pants
[edit: he augered doing this so I got the kill]
The most you'd get out of me if you surprised me would be a "Huh? I'm being shot at? Oh, how'd he get there?"